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Create View

CREATE VIEW [IF NOT EXISTS] [db_name.]view_name [(column_name [COMMENT column_comment], ...) ]
  [COMMENT view_comment]
  [TBLPROPERTIES (property_name = property_value, ...)]
  AS SELECT ...;

CREATE VIEW creates a view with the given name. An error is thrown if a table or view with the same name already exists. You can use IF NOT EXISTS to skip the error.

If no column names are supplied, the names of the view's columns will be derived automatically from the defining SELECT expression. (If the SELECT contains unaliased scalar expressions such as x+y, the resulting view column names will be generated in the form _C0, _C1, etc.) When renaming columns, column comments can also optionally be supplied. (Comments are not automatically inherited from underlying columns.)

A CREATE VIEW statement will fail if the view's defining SELECT expression is invalid.

Note that a view is a purely logical object with no associated storage. (No support for materialized views is currently available in Hive.) When a query references a view, the view's definition is evaluated in order to produce a set of rows for further processing by the query. (This is a conceptual description; in fact, as part of query optimization, Hive may combine the view's definition with the query's, e.g. pushing filters from the query down into the view.)

A view's schema is frozen at the time the view is created; subsequent changes to underlying tables (e.g. adding a column) will not be reflected in the view's schema. If an underlying table is dropped or changed in an incompatible fashion, subsequent attempts to query the invalid view will fail.

Views are read-only and may not be used as the target of LOAD/INSERT/ALTER. For changing metadata, see ALTER VIEW.

A view may contain ORDER BY and LIMIT clauses. If a referencing query also contains these clauses, the query-level clauses are evaluated after the view clauses (and after any other operations in the query). For example, if a view specifies LIMIT 5, and a referencing query is executed as (select * from v LIMIT 10), then at most 5 rows will be returned.

Starting with Hive 0.13.0, the view's select statement can include one or more common table expressions (CTEs) as shown in the SELECT syntax. For examples of CTEs in CREATE VIEW statements, see Common Table Expression.

CREATE VIEW onion_referrers(url COMMENT 'URL of Referring page')
  COMMENT 'Referrers to The Onion website'
  AS
  SELECT DISTINCT referrer_url
  FROM page_view
  WHERE page_url='http://www.theonion.com';

Use SHOW CREATE TABLE to display the CREATE VIEW statement that created a view. As of Hive 2.2.0, SHOW VIEWS displays a list of views in a database.

Drop View

DROP VIEW [IF EXISTS] [db_name.]view_name;

DROP VIEW removes metadata for the specified view. (It is illegal to use DROP TABLE on a view.)

When dropping a view referenced by other views, no warning is given (the dependent views are left dangling as invalid and must be dropped or recreated by the user).

In Hive 0.7.0 or later, DROP returns an error if the view doesn't exist, unless IF EXISTS is specified or the configuration variable hive.exec.drop.ignorenonexistent is set to true.

DROP VIEW onion_referrers;

Alter View Properties

ALTER VIEW [db_name.]view_name SET TBLPROPERTIES table_properties;

table_properties:
  : (property_name = property_value, property_name = property_value, ...)

As with ALTER TABLE, you can use this statement to add your own metadata to a view.

Alter View As Select

ALTER VIEW [db_name.]view_name AS select_statement;

Alter View As Select changes the definition of a view, which must exist. The syntax is similar to that for CREATE VIEW and the effect is the same as for CREATE OR REPLACE VIEW.

Note: The view must already exist, and if the view has partitions, it could not be replaced by Alter View As Select.

These statements provide a way to query the Hive metastore for existing data and metadata accessible to this Hive system.

Show Databases

SHOW (DATABASES|SCHEMAS) [LIKE 'identifier_with_wildcards'];

SHOW DATABASES or SHOW SCHEMAS lists all of the databases defined in the metastore. The uses of SCHEMAS and DATABASES are interchangeable – they mean the same thing.

The optional LIKE clause allows the list of databases to be filtered using a regular expression. Wildcards in the regular expression can only be '*' for any character(s) or '|' for a choice. Examples are 'employees', 'emp*', 'emp*|*ees', all of which will match the database named 'employees'.

Show Tables/Views/Partitions/Indexes

Show Tables

SHOW TABLES [IN database_name] ['identifier_with_wildcards'];

SHOW TABLES lists all the base tables and views in the current database (or the one explicitly named using the IN clause) with names matching the optional regular expression. Wildcards in the regular expression can only be '*' for any character(s) or '|' for a choice. Examples are 'page_view', 'page_v*', '*view|page*', all which will match the 'page_view' table. Matching tables are listed in alphabetical order. It is not an error if there are no matching tables found in metastore. If no regular expression is given then all tables in the selected database are listed.

Show Views

SHOW

SHOW VIEWS [IN/FROM database_name] [LIKE] ['pattern_with_wildcards'];

SHOW VIEWS lists all the views in the current database (or the one explicitly named using the IN or FROM clause) with names matching the optional regular expression. Wildcards in the regular expression can only be '*' for any character(s) or '|' for a choice. Examples are 'page_view', 'page_v*', '*view|page*', all which will match the 'page_view' view. Matching views are listed in alphabetical order. It is not an error if no matching views are found in metastore. If no regular expression is given then all views in the selected database are listed.

SHOW VIEWS;                                -- show all views in the current database
SHOW VIEWS 'test_*';                       -- show all views that start with "test_"
SHOW VIEWS '*view2';                       -- show all views that end in "view2"
SHOW VIEWS LIKE 'test_view1|test_view2';   -- show views named either "test_view1" or "test_view2"
SHOW VIEWS FROM test1;                     -- show views from database test1
SHOW VIEWS IN test1;                       -- show views from database test1. (FROM and IN are same) 
SHOW VIEWS IN test1 "test_*";              -- show views from database test2 that start with "test_"

Show Partitions

SHOW PARTITIONS table_name;

SHOW PARTITIONS lists all the existing partitions for a given base table. Partitions are listed in alphabetical order.

It is also possible to specify parts of a partition specification to filter the resulting list.

SHOW PARTITIONS table_name PARTITION(ds='2010-03-03');            -- (Note: Hive 0.6 and later)
SHOW PARTITIONS table_name PARTITION(hr='12');                    -- (Note: Hive 0.6 and later)
SHOW PARTITIONS table_name PARTITION(ds='2010-03-03', hr='12');   -- (Note: Hive 0.6 and later)

SHOW PARTITIONS [db_name.]table_name [PARTITION(partition_spec)];   -- (Note: Hive 0.13.0 and later)

SHOW PARTITIONS databaseFoo.tableBar PARTITION(ds='2010-03-03', hr='12');   -- (Note: Hive 0.13.0 and later)

Show Table/Partition Extended

SHOW TABLE EXTENDED [IN|FROM database_name] LIKE 'identifier_with_wildcards' [PARTITION(partition_spec)];

SHOW TABLE EXTENDED will list information for all tables matching the given regular expression. Users cannot use regular expression for table name if a partition specification is present. This command's output includes basic table information and file system information like totalNumberFiles, totalFileSize, maxFileSize, minFileSize,lastAccessTime, and lastUpdateTime. If partition is present, it will output the given partition's file system information instead of table's file system information.

hive> show table extended like part_table;
OK
tableName:part_table
owner:thejas
location:file:/tmp/warehouse/part_table
inputformat:org.apache.hadoop.mapred.TextInputFormat
outputformat:org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
columns:struct columns { i32 i}
partitioned:true
partitionColumns:struct partition_columns { string d}
totalNumberFiles:1
totalFileSize:2
maxFileSize:2
minFileSize:2
lastAccessTime:0
lastUpdateTime:1459382233000

Show Table Properties

SHOW TBLPROPERTIES tblname;
SHOW TBLPROPERTIES tblname("foo");

The first form lists all of the table properties for the table in question one per row separated by tabs. The second form of the command prints only the value for the property that's being asked for.

Show Create Table

SHOW CREATE TABLE ([db_name.]table_name|view_name);

SHOW CREATE TABLE shows the CREATE TABLE statement that creates a given table, or the CREATE VIEW statement that creates a given view.

Show Indexes

SHOW [FORMATTED] (INDEX|INDEXES) ON table_with_index [(FROM|IN) db_name];

SHOW INDEXES shows all of the indexes on a certain column, as well as information about them: index name, table name, names of the columns used as keys, index table name, index type, and comment. If the FORMATTED keyword is used, then column titles are printed for each column.

Show Columns

SHOW COLUMNS (FROM|IN) table_name [(FROM|IN) db_name];

SHOW COLUMNS shows all the columns in a table including partition columns.

Show Functions

SHOW FUNCTIONS "a.*";

SHOW FUNCTIONS lists all the user defined and builtin functions matching the regular expression. To get all functions use ".*"

Show Granted Roles and Privileges

Hive Default Authorization - Legacy Mode has information about these SHOW statements:

• SHOW ROLE GRANT
• SHOW GRANT

In Hive 0.13.0 and later releases, SQL standard based authorization has these SHOW statements:

• SHOW ROLE GRANT
• SHOW GRANT
• SHOW CURRENT ROLES
• SHOW ROLES
• SHOW PRINCIPALS

Show Locks

SHOW LOCKS <table_name>;
SHOW LOCKS <table_name> EXTENDED;
SHOW LOCKS <table_name> PARTITION (<partition_spec>);
SHOW LOCKS <table_name> PARTITION (<partition_spec>) EXTENDED;
SHOW LOCKS (DATABASE|SCHEMA) database_name;     -- (Note: Hive 0.13.0 and later; SCHEMA added in Hive 0.14.0)

SHOW LOCKS displays the locks on a table or partition. See Hive Concurrency Model for information about locks.

SHOW LOCKS (DATABASE|SCHEMA) is supported from Hive 0.13 for DATABASE (see HIVE-2093) and Hive 0.14 for SCHEMA (see HIVE-6601). SCHEMA and DATABASE are interchangeable – they mean the same thing.

When Hive transactions are being used, SHOW LOCKS returns this information (see HIVE-6460):

• database name
• table name
• partition name (if the table is partitioned)
• the state the lock is in, which can be:
  • "acquired" – the requestor holds the lock
  • "waiting" – the requestor is waiting for the lock
  • "aborted" – the lock has timed out but has not yet been cleaned up
• Id of the lock blocking this one, if this lock is in "waiting" state
• the type of lock, which can be:
  • "exclusive" – no one else can hold the lock at the same time (obtained mostly by DDL operations such as drop table)
  • "shared_read" – any number of other shared_read locks can lock the same resource at the same time (obtained by reads; confusingly, an insert operation also obtains a shared_read lock)
  • "shared_write" – any number of shared_read locks can lock the same resource at the same time, but no other shared_write locks are allowed (obtained by update and delete)
• ID of the transaction this lock is associated with, if there is one
• last time the holder of this lock sent a heartbeat indicating it was still alive
• the time the lock was acquired, if it has been acquired
• Hive user who requested the lock
• host the user is running on
• agent info – a string that helps identify the entity that issued the lock request. For a SQL client this is the query ID, for streaming client it may be Storm bolt ID for example.

Show Conf

SHOW CONF <configuration_name>;

SHOW CONF returns a description of the specified configuration property.

• default value
• required type
• description

Note that SHOW CONF does not show the current value of a configuration property. For current property settings, use the "set" command in the CLI or a HiveQL script (see Commands) or in Beeline (see Beeline Hive Commands).

Show Transactions

SHOW TRANSACTIONS;

SHOW TRANSACTIONS is for use by administrators when Hive transactions are being used. It returns a list of all currently open and aborted transactions in the system, including this information:

• transaction ID
• transaction state
• user who started the transaction
• machine where the transaction was started

Show Compactions

SHOW COMPACTIONS;

SHOW COMPACTIONS returns a list of all tables and partitions currently being compacted or scheduled for compaction when Hive transactions are being used, including this information:

• database name
• table name
• partition name (if the table is partitioned)
• whether it is a major or minor compaction
• the state the compaction is in, which can be:
  • "initiated" – waiting in the queue to be compacted
  • "working" – being compacted
  • "ready for cleaning" – the compaction has been done and the old files are scheduled to be cleaned
  • "failed" - the job failed. metastore log will have more detail
  • "succeeded" - A-ok
  • "attempted" - Initiator attempted to schedule a compaction but failed. metastore log will have more info.
• thread ID of the worker thread doing the compaction (only if in working state)
• the time at which the compaction started (only if in working or ready for cleaning state)

Compactions are initiated automatically, but can also be initiated manually with an ALTER TABLE COMPACT statement.